1. Field of the Invention
The invention relates to a pipe construction kit comprising a first and a second pipe section of plastic material, each of which having a smooth-walled cylindrical internal pipe and a corrugated external pipe with annular cylindrical elevations and troughs, and an outside diameter D4; a socket, which is in-line molded on one end of the first pipe section, having an outside diameter D18 and an inside diameter D17; and a spigot, which is in-line molded on an end of the second pipe section, comprising the internal pipe and a second external pipe section, and having an outside diameter D22, to which the following applies in relation to the inside diameter D17 of the socket: D22≈D17.
2. Background Art
A pipe construction kit of the generic type is known from U.S. Pat. No. 5,071,173. This known design includes a smooth-walled pipe socket, the outside diameter of which does not project over the outside diameter of the elevations of the pipe sections. In this way, this known design enables the pipe construction kits of the species to be used for sewer pipe reconstruction, because the consecutively joined-on pipe sections have a uniform maximum outside diameter. Likewise, this design of a pipe socket has the advantage that transporting the pipe sections which have a socket at one end and a spigot at the other is possible without the risk of socket damaging. If the spigot also has an outside diameter that corresponds to the outside diameter of the pipe sectionsxe2x80x94which is prior artxe2x80x94and if, consequently, the socket has an internal diameter that corresponds at least to the outside diameter of the pipe sections, then there is the risk of the socket being damaged during transportation. Moreover, the socket does not impede the insertion of interconnected pipes in conduits and the like. The internal pipes of these twin-wall pipes are smooth-walled, having, however, some minor manufacturing irregularity. The term xe2x80x9csmooth-walledxe2x80x9d as employed in this application also includes this minor irregularity.
In the case of great nominal widths, for instance in the case of nominal widthsxe2x89xa7DN 400, there is the problem of sockets that have smooth walls internally and externally no longer being sufficiently stable.
U.S. Pat. No. 5,992,469 teaches to provide sockets that are in-line molded on corrugated twin-wall pipes also in the form of twin-wall pipes over part of their axial length, having a smooth-walled internal pipe section and a corrugated external pipe section with elevations and troughs. This known design has the drawback that the outside diameter of the socket distinctly exceeds the outside diameter of the pipe sections, because the respective regular pipe section is also employed as a spigot.
It is an object of the invention to embody a pipe construction kit of the generic type in such a way that high stability of the pipe socket is reached and the advantages of the species are maintained.
According to the invention, this object is attained in that the socket is a twin-wall pipe having a smooth-walled internal pipe section and a corrugated first external pipe section with elevations and troughs. The gist of the invention resides in that the spigot as well as the socket are twin-wall-pipe sections with the available overall height of the elevations of the pipe sections, inclusive of the thickness of the internal pipes of the pipe sections, being split up among the height of the elevations, inclusive of the internal pipe section of the socket, and the height of the elevations and of the internal pipe of the spigot. A favorable splitting ratio is reflected by 0.3 (H18+H22)xe2x89xa6H18xe2x89xa60.7(H18+H22) applying to the radial height H18 of the socket as compared to the radial height H22 of the spigot.
The elevations of the socket on the one hand and of the spigot on the other have a clearly smaller spacing than the elevations of the pipe sections. Favorable relations of this are reflected by 0.3 T5xe2x89xa6T19xe2x89xa60.7 T5 applying to the spacing T5 of the elevations of the pipe sections as compared to the spacing T19 of the socket, and by 0.3 T5xe2x89xa6T23xe2x89xa60.7 T5 applying to the spacing T5 of the elevations of the pipe sections as compared to the spacing T23 of the elevations of the spigot.
Further features, advantages and details of the invention will become apparent from the ensuing description of an exemplary embodiment, taken in conjunction with the drawing.